I think that putting the chats there would then block people going to the decarder and refiner. Also, players generally put up chats wherever they feel like. Our rule is that they must be at least 3 cells away from an NPC. Sometimes, they still block the NPCs, but a GM will move them. I know that the chats may be inconvenient, but players use the center of Forsaken City to attract more people to trade, buy, or sell items to. Most of the NPCs around that area are non-essential. For example, the job changing and stat resetting NPCs are always clear of chats.